Ethane oxidative dehydrogenation mechanism on MoO₃(010) surface: A first-principle study using on-site Coulomb correction

We applied the PBE+U method to investigate the mechanism of ethane oxidative dehydrogenation reaction (ODH) on the MoO₃(010) surface. Our systematic study shows that ethylene generation is energetically a favorable pathway from the horizontal C₂H₆ adsorption. The vertical adsorption of C₂H₆ leads to the aldehyde generation along the α-oxidative dehydrogenation pathway (α-ODH). However, along the β-ODH pathway, the ethylene oxide formation is identified as the final product but may transform to produce ethylene from the CH₂CH₂O intermediate. The formation energy of oxygen vacancy (ΔE_f ^v) of all types of oxygen atoms of the MoO₃(010) surface are characterized with the on-site Coulomb correction, being reasonably consistent with the HSE results. The U correction leads to the mismatching between the d_z ² orbital of Mo and p_z orbitals of the terminal oxygen and consequently weakens the Mo–O chemical bond. Therefore, the weakened Mo–O chemical bond can increase the possibility of forming the oxygenated species, such as aldehyde and ethylene oxide.